What is the optional 4-eyes principle (dual control) for safe locks?

The 4-eyes principle — also called dual control or dual-code mode — is an optional setting available on many electronic safe locks. When it is switched on, the safe only opens after two authorised people have each entered their own separate, valid code one after the other; a single code is no longer enough on its own.

It is mainly used where cash or valuables should never be accessible to one person alone — for example retail cash offices, pharmacies, hotels, jewellers and other high-value or shared environments. Because two people must be present together to open the safe, it reduces the risk of internal theft and removes the incentive for a robber to coerce a single keyholder.

Each user keeps their own personal code, so on locks with an audit trail you can still see who took part in an opening. The feature is optional and can usually be enabled or disabled in the lock's programming menu, so you can run the safe in normal single-code mode and switch to dual control only when you need the extra control.

The 4-eyes principle is a function of the electronic lock, not the safe body, so it is only available on safes fitted with a lock that supports it. If dual control matters for your setup, check the lock specification before ordering, or ask our advisors and we will confirm which models support it.